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排序方式: 共有475条查询结果,搜索用时 31 毫秒
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以水热法并进一步焙烧合成脊椎状NiCo2O4纳米棒,通过透射电子显微镜(TEM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)和热重分析仪(TG)等来表征其结构形态及热稳定性.采用线性扫描法(LSV)、循环伏安(CV)研究所制备催化剂的在玻碳和旋转圆盘电极上的电催化活性:在0.1 mol·L-1 KOH溶液中的电催化析氧反应(OER)和电催化氧还原反应(ORR).研究结果表明,所制备的脊椎状NiCo2O4纳米棒有大量的不饱和态,200℃焙烧制备的脊椎状NiCo2O4纳米棒析氧过电位最小可达309 mV,Tafel斜率145.6 mV/dec,其氧还原极限电流密度在1600 rmp可达到5.095 mA·cm-2,电子转移数在3.2~3.8之间,接近四电子转移机理,其优良电化学性能可能是由于暴露了更多的边缘缺陷的缘故. 相似文献
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ZHANG Li-Chun WU Yue-Qin LI Huai-Fan ZHAO Ren 《理论物理通讯》2008,50(7):97-100
Recently, there has been much attention devoted to resolving the quantum corrections to the Bekenstein- Hawking black hole entropy. The different correction leading terms are obtained by the different methods. In this paper, we calculate the correction to SAdS5 black hole thermodynamic quantity due to the generalized uncertainty principle. Furthermore we derive that the black hole entropy obeys Bekenstein Hawking area theorem. The entropy has infinite correction terms. And every term is finite and calculable. The corrected Cardy-Vedinde formula is derived. In our calculation, Bekenstein Hawking area theorem still holds after considering the generalized uncertainty principle. We have not introduced any hypothesis. The calculation is simple. Physics meaning is clear. We note that our results are quite general. It is not only valid for four-dimensional spacetime but also for higher-dimensional SAdS spacetime. 相似文献
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Yong-Li Xu Yin-Lu Han Xin-Wu Su Xiao-Jun Sun Hai-Ying Liang Hai-Rui Guo Chong-Hai Cai 《中国物理C(英文版)》2020,44(12):124103-124103-10
We construct a new global optical model potential to describe the elastic scattering of 12C. The experimental data of elastic-scattering angular distributions and total reaction cross sections for targets from 24Mg to 209Bi are considered below 200 MeV within the framework of the optical model. The results calculated using the derived global optical potential are then compared with the existing experimental data. The reliability of the global optical potential is further tested by predicting the elastic scattering data out of the mass and energy ranges, within which the global potential parameters are determined, and reasonable results are also obtained. 相似文献
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Elastic scattering angular distributions and total reaction cross-sections of ~(7,10,11,12)Be projectiles are predicted by the systematic ~9 Be global phenomenological optical model potential for target mass numbers ranging from24 to 209. These predictions provide a detailed analysis by their comparison with the available experimental data.Furthermore, these elastic scattering observables are also predicted for some targets out of the mass number range.The results are in reasonable agreement with the existing experimental data, and they are presented in this study. 相似文献
48.
双矿化剂对合成ZSM分子筛酸性和织构特征及其甲醇转化制丙烯催化性能的影响 《燃料化学学报》2018,46(8):967-976
采用静态水热法在F--OH-体系中,以四丙基氢氧化铵为模板剂、偏铝酸钠为铝源、正硅酸乙酯为硅源,合成了纳米SiO2-ZSM-5分子筛,考察了F-/Al2O3物质的量比对所合成的ZSM-5分子筛织构性质和甲醇转化制丙烯催化性能的影响。结果发现,随着初始溶胶F-/Al2O3物质的量比的增大,产物中SiO2的含量增大,ZSM-5分子筛的相对结晶度有所降低;同时,分子筛的比表面积和孔容减小、酸强度降低、酸量减少。对于甲醇转化制丙烯,最佳F-/Al2O3物质的量比为12;此时,丙烯选择性高于45%,丙烯/乙烯(P/E)比值大于10。反应机理分析表明,过渡态择形选择性是控制烯烃选择性的重要因素。 相似文献
49.
电催化析氧反应(OER)是电解水制氢的重要半电池反应。然而,OER的缓慢动力学仍需研究高效的电催化剂。在非贵金属催化剂中,NiFe基材料是OER催化剂研究热点。本文通过食人鱼溶液简单一步浸渍刻蚀法将不同Fe含量的泡沫NiFe合金进行氧化,制备了表面具有纳米片形貌的NiFeOOH自支撑电催化剂,并深入研究其电催化析氧性能。通过SEM、XRD、XPS等对电催化剂的形貌结构及成分进行表征,证实了三维多孔基底上NiFeOOH纳米片结构的形成。由于高价镍、铁物种的存在以及二维纳米片结构的生成,NiFeOOH/NF的析氧性能大幅度提高,在10 mA?cm-2的电流密度下过电位仅155.68 mV,Tafel斜率为 88.2 mV?dec-1。这为研制高效、耐用的自支撑非贵金属电极提供了新思路。 相似文献
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A new sensitive and selective chromogenic reagent, 1-azobenzene-3-(3-hydroxyl-2-pyridyl)-triazene (ABHPT), was synthesized. It has been found that ABHPT reacts with nickel(II) in a borax buffer solution (pH 10.0) to form 2: 1
red complexes with the maximum absorption at 530 nm. The apparent molar absorptivity of the complex is 2.6 × 105 L/(mol cm). Most metal ions can be tolerated in considerable amounts, whereby only zinc and mercury may interfere with the
determination of nickel(II). Nevertheless, this can be easily eliminated by prior separation with sulfhydryl dextran gel.
A new method for the spectrophotometric determination of trace nickel(II) was developed. Beer’s law is obeyed for 0–15 μg
of nickel(II) in 25 mL of solution. The limit of quantification, limit of detection, and relative standard deviation are 0.74
ng/mL, 0.25 ng/mL, and 1.0%, respectively. The method has been applied to the determination of trace nickel(II) in biological
samples with satisfactory results.
The text was submitted by the authors in English. 相似文献